Flexible and highly sensitive humidity sensors using screen-printed TiO2 nanoparticles as sensitive layer

Abstract

In this work, we present an original example of flexible and miniaturized humidity sensor using screen-printed TiO2 nanoparticles as sensitive layer. The proposed sensors operate under room-temperature conditions and exhibit high sensitivity to changes in relative humidity. The humidity sensor consists of a TiO2-based sensitive nanomaterial printed on the top of interdigitated electrodes (IDEs) patterned by laser ablation on flexible substrate. A TiO2 screen-printing paste from commercially-available nanopowders was developed in order to allow large-scale fabrication of humidity sensors at low temperature. The I-V characteristic of the sensor shows good linearity and resistance measurements confirm the water vapour's absorption on the sensitive layer, showing high sensitivity in the range of 24 to 90% relative humidity, while exhibiting relatively fast response and recovery times, without the need of any refreshing method.